Methods of identification from Christchurch earthquake
Currently a lot of research revolves around developing accurate methods of determining the origins of degraded DNA, in particular burnt remains and disaster victims, as well as developing faster methods to determine DNA degradation. The identification of disaster victims is often hampered due to the severe fragmentation, decomposition and intermixing of the remains of multiple victims because of the environmental conditions they have been exposed to (Ziętkiewicz et al. 2011).
Artistic image of damaged DNA
Manjunath et al. (2011) found that teeth are an excellent source of DNA material, especially in the root body, as they are resistant to environmental assault, for example incineration, immersion, trauma, mutilation and decomposition. They found that teeth were an exceptional source for high molecular weight mtDNA which is useful when extensive DNA degradation can lead to failure of STR analysis (Manjunath et al. 2011).
Dentition at work
Remains that have been damaged by fire are of particular concern to the forensic community as these remains are often not able to be identified through visual means, although dentition or fingerprinting may be available, therefore they frequently require an analysis of their DNA for identification but the DNA of a burn victim is often degraded, although the degree of degradation depends on the degree of burning suffered (Schwark et al. 2010).
Schwark et al. (2010) undertook a study on the reliability of DNA analysis at different thermal impacts, where they found that well preserved and semi-burnt bones gave a full screening profile; black burnt bones gave variable results, from a full profile to a complete allelic drop-out; while blue-grey and blue-grey-white bones frequently produced in negative results and when they did get results it was mostly from mtDNA.
Blue-grey-white burnt bones
There has been some success with the development of an assay that will allow geneticist to determine the level of degradation of a sample before they begin their analysis therefore allowing them to choose the method which will best afford them the greatest results, but it is currently unrealistic to use it unless a sample is known to have been exposed to conditions conducive to DNA degradation (Nicklas et al. 2011).
Currently a lot of research revolves around developing accurate methods of determining the origins of degraded DNA, in particular burnt remains and disaster victims, as well as developing faster methods to determine DNA degradation. The identification of disaster victims is often hampered due to the severe fragmentation, decomposition and intermixing of the remains of multiple victims because of the environmental conditions they have been exposed to (Ziętkiewicz et al. 2011).
Remains that have been damaged by fire are of particular concern to the forensic community as these remains are often not able to be identified through visual means, although dentition or fingerprinting may be available, therefore they frequently require an analysis of their DNA for identification but the DNA of a burn victim is often degraded, although the degree of degradation depends on the degree of burning suffered (Schwark et al. 2010).
Schwark et al. (2010) undertook a study on the reliability of DNA analysis at different thermal impacts, where they found that well preserved and semi-burnt bones gave a full screening profile; black burnt bones gave variable results, from a full profile to a complete allelic drop-out; while blue-grey and blue-grey-white bones frequently produced in negative results and when they did get results it was mostly from mtDNA.
There has been some success with the development of an assay that will allow geneticist to determine the level of degradation of a sample before they begin their analysis therefore allowing them to choose the method which will best afford them the greatest results, but it is currently unrealistic to use it unless a sample is known to have been exposed to conditions conducive to DNA degradation (Nicklas et al. 2011).
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